A recently published retrospective cohort study has reported notable variations in long-term outcomes between different endodontic treatment protocols. The research, which analysed over 14,000 endodontically treated teeth with a five to 10 years of follow-up, suggests that the choice of treatment protocol may have a measurable impact on tooth survival and the likelihood of subsequent intervention.
Published in the International Endodontic Journal, the study examined 14,233 teeth treated over 25 years, making it one of the largest in-vivo investigations of its kind. The research aimed to compare three commonly used endodontic protocols and assess their outcomes using analytical methods such as entropy balancing and multistate analysis.
Comparison of three endodontic protocols
The study was conducted by researchers from Christian-Albrechts-University Kiel (Germany), October University for Modern Sciences and Arts (Egypt), and the Dental Academy for Continuing Professional Development (Germany). It evaluated three treatment protocols:
• Protocol one: Traditional treatment using hand files (n = 5,450)
• Protocol two: Rotary NiTi systems (n = 1,667)
• Protocol three: A protocol incorporating Reciproc instruments along with passive ultrasonic irrigation (PUI), EDTA, apex locators, warm vertical obturation, and a calcium silicate-based sealer (n = 7,116). This protocol was carried out without an initial glide path in most cases, in line with manufacturer instructions, with manual glide path preparation only when necessary
Key findings
Across the long-term follow-up period, protocol three was associated with higher rates of tooth survival and lower rates of both surgical and non-surgical retreatment compared with the other two protocols. According to the published data:
• Long-term tooth survival without further intervention was 30-40% higher with protocol three
• Non-surgical retreatment occurred 66% less frequently
• Surgical retreatment incidence was 57% lower
• Tooth extraction rates were 21% lower
The authors noted that specific features of the Reciproc system — such as its ability to reach working length without an initial glide path — may have contributed to the observed outcomes, though they emphasised that further research would be beneficial to confirm causation and explore underlying factors.
Expert perspectives
Commenting on the findings, Prof Ghassan Yared, who developed single-file reciprocation and the Reciproc Blue system, highlighted that the study provides extensive long-term data supporting the effectiveness of protocols that include reciprocating instruments.
Mathias Kraus, vice-president of endodontic solutions at Dentsply Sirona, stated that the research may give clinicians confidence in adopting evidence-based protocols designed to enhance treatment predictability and workflow efficiency.
All images courtesy of Dentsply Sirona.
